This invention pertains to the art of filters and more particularly to liquid filters.
The invention is particularly applicable to a permanent, reuseable filter for coffee brewing apparatus and will be described with reference to such a construction which is adapted for use with one type coffee brewing apparatus where the filter has a somewhat oblong conformation. However, it will be appreciated by those skilled in the art that the concepts of the invention have broader applications and may be utilized in other environments and apparatus for filtering other liquids and liquid-like substances.
Drip type coffee makers have been used in commercial establishments for many years. In recent years, however, drip type coffee makers for home use have been introduced in the marketplace and have received wide customer recognition. Basically, drip type coffee makers utilize prepackaged or a measured amount of dry coffee granules placed in a filter basket or filter support which may be placed in communication with a source of hot water. A predetermined amount of hot water is introduced into the filter basket to intermix with the coffee granules and to be converted into coffee. This coffee then flows from the bottom area of the filter basket into a conventional serving container or carafe. There are many different types and styles of such coffee makers with one type of apparatus finding particular commercial success in the European market. Generally, in this type of apparatus, the so-called filter basket or holder rests directly on the serving container or carafe to receive hot water from a convenient source.
In conjunction with drip coffee makers, a filter is inserted into the filter basket which, in turn, receives the coffee granules. This filter acts to prevent the granules or grounds themselves from undesirably passing through the filter basket into the serving container or carafe. Heretofore, the vast majority of these filters have been constructed from a paper-like material. As such, they are only useable once and then discarded along with the coffee grounds when brewing has been completed. With regard to the type of brewing apparatus specifically noted above, the paper filters are packaged in quantity in a flattened condition and are constructed to be foldable into or assume a generally oblong, somewhat conical cup-shaped configuration generally compatible with the filter support.
Because of the necessity for using a new filter for each pot of coffee brewed and because of the attendant storage spaced required to maintain an adequate inventory or supply of such filters, it has been found desirable to develop a permanent type, reuseable filter construction particularly suited for use in such brewing apparatus. The present invention provides a new filter design and construction which meets these needs and which is easy to manufacture, inexpensive to manufacture, reuseable for an extended period of time and readily adapted to use in a number of different environments for filtering different liquids.